I know this is not about the PPA version, but maybe this "workaround" will help to track down the cause. On opening a Writer file from Nautilus, a duplicate but low-res blue Writer icon appears in the dock. Opening a second Writer file produces TWO new icons in the dock: one low-res blue Writer, and one blank white (empty document). I found out that resetting Unity (unity --reset) fixes the dock's behaviour -- I get two arrows next to a single Writer laucher icon. However, if after that I open a third file, the dock still produces a duplicate icon.
I know this is not about the PPA version, but maybe this "workaround" will help to track down the cause. On opening a Writer file from Nautilus, a duplicate but low-res blue Writer icon appears in the dock. Opening a second Writer file produces TWO new icons in the dock: one low-res blue Writer, and one blank white (empty document). I found out that resetting Unity (unity --reset) fixes the dock's behaviour -- I get two arrows next to a single Writer laucher icon. However, if after that I open a third file, the dock still produces a duplicate icon.
Ubuntu 12.04 (64-bit), Unity 5.20, libreoffice 4.1.3~rc2 (PPA)